1.9 Wont Start, Injectors Not Fueling

[kevvy555 0]

Hi,

 

I have recently rebuilt my 1.9 gti engine in my rally car, i have had it running since and it ran fine (sat for 50 minutes at the MOT station), but now after it failing to start on and off it wont start at all. When i could get it running, when it warmed up it wouldn't start.

 

Here is what i have done found out upto now:

 

AFM was know to be faulty so replaced with a working one.

Jetronic injection system, so NO crank sensor etc, its an XU9JA as far as i can tell.

Tested the throttle position sensor and replaced as was faulty.

Replaced the wrong (had a 1.6 one in) ECU with a good one for a 1.9.

Have checked for spark and there is definitely one.

Have also got new plugs and coil.

Have tested the ecu temperature sensor which reads correctly for it been cold (was 14c).

Fuel pump works, its on a separate switch, plenty of fuel coming through.

 

So i took the injectors out and turned it over, no fuel coming from the injectors (it even started briefly with the excess fuel that came out of one of the injectors that popped off).

 

Tested the voltage coming from the injector plugs while turning over the engine and it registers 0.02v, which i believe it should have 12v.

 

So, as far as i can see i have no voltage to the injectors so they wont work.

 

Suspect problems:

 

tachymetric relay: Does this supply voltage to the injectors as well as control the fuel pump (if not on a switch), when i press the ignition (has a push start) i can feel the relay activate and when i stop cranking it resets itself - seems ok but unsure.

 

Injection Supply Relay - Do they have one of these, haynes manual has it in the wiring diagram but i cant find it on the car, would be a logical culprit though.

 

Bad wiring - could be this as it has a cut down loom on it, problem im having is working out what to test from the injectors to where ever to find out if it is a faulty wire.

 

Wire from dizzy to ecu - Not sure how to trace if this works but it would also make sense if the ecu wasnt getting this signal.

 

Have had it suggested it could be the injector plugs shorting but can find any bad wires etc.

 

I think i have covered everything there, any help would be much appreciated as im running out of options, its probably something simple.

 

Cheers

 

Kev

 

 

 

 

 

 

 

[Leet205 48]

Have you tried popping the plugs off the injectors to see if any of the wires have been pushed back? If there is one not making contact it will cause all not to fire

 

when testing your injectors have the ignition on and test one pin at a time and earth onto the inlet manifold, one should have around 12v

 

Hope this helps - I have just sorted mine and this was the issue!

[kevvy555 0]

Will have a closer look at the injector plugs, makes sense on how you say to test them, thanks for the help.

[DamirGTI 325]

 

So i took the injectors out and turned it over, no fuel coming from the injectors (it even started briefly with the excess fuel that came out of one of the injectors that popped off).

 

Tested the voltage coming from the injector plugs while turning over the engine and it registers 0.02v, which i believe it should have 12v.

 

So, as far as i can see i have no voltage to the injectors so they wont work.

 

Suspect problems:

 

tachymetric relay: Does this supply voltage to the injectors as well as control the fuel pump (if not on a switch), when i press the ignition (has a push start) i can feel the relay activate and when i stop cranking it resets itself - seems ok but unsure.

 

Injection Supply Relay - Do they have one of these, haynes manual has it in the wiring diagram but i cant find it on the car, would be a logical culprit though.

 

Bad wiring - could be this as it has a cut down loom on it, problem im having is working out what to test from the injectors to where ever to find out if it is a faulty wire.

 

Wire from dizzy to ecu - Not sure how to trace if this works but it would also make sense if the ecu wasnt getting this signal.

 

Cheers

 

Kev

 

 

 

 

 

 

 

 

Hi and welcome on our forum !

 

 

Tachymetric relay - yes , it does feed the injectors as well as the fuel pump . It's a common problem , unplug the relay from the connector and inspect connector pins .. also , pop off the relay cover and take a look at the relay insides - carefully , if the relay coil winding has a broken wire connection , check for burnt diodes , resistors (i had burnt diode on mine once , and the symptoms where quite a bit similar to yours if not the same) check for loosen soldered joints . Sometimes just an quick/easy blast with an piece of fine sanding paper over the main relay coil triggering contact restores it's function ..

Or simply , if you have an known good spare relay - try it and see if it sort out the issue .

 

Injection Supply Relay - Jetronic engine management doesn't have one , it's fitted on later 205's with Motronic engine management which controls fueling and spark via ECU .

 

Bad wiring - well , cod always be an issue on a 205's .. electrics/wiring loom is quite a bit poor with old fashion connectors which often breaks loose , oxidize because of lack of joint hermetic insulation etc. I can't remember from top of my head , but if i remember an white'ish wire is the one which goes from the tachymetric relay connector onto the injectors , though color identifying wiring is not accurate because it varies from the model/year of build . Anyway , it's the wire No. 18 (each wire has a stamped number/letter , like 16A , on the insulation just a few inches from the end and beginning of the wire .. and by this you can identify which wire is which by tracking it trough wiring diagram) , there's also wire No 16 (should be green) which connects injectors with the ECU - check them with an multimeter for continuity . Wire breakage or touching ground of the two said wires will result with no power/signal on the injectors . Check the injector earths as well .

 

Wire from dizzy to ecu (not quite the ECU , it connects the ignition amplifier) - cod be that as well , however if the dizzy signal cable is bad you'll be left without both the spark and the fuel . For testing the actual signal of the dizzy pick up coil via said cable - try searching the forum database by my user-name (i've posted pictures in few threads back in the days of the cable connector layout and wrote the explanation how to test it with an multimeter) . Simple test you can try is , ask someone to help you cranking the engine , grab the cable and try shaking it , twisting , bending .. if it's bad , and you can get the engine starting you'll notice changes as you wiggle the cable , or if it sprung/starts while willing .

Also , the signal cable has an 3pin yellow connector which then connects into a black one (in line connected "male" in "female" connector) undo the clip and separate the joint and clean the pins inside the connectors with some contact cleaner and an piece of sanding paper (as said , because of poor wiring insulation from moisture , these often oxidize)

 

"Push start" and fuel pump on a "separate switch" - if already done this way rather than OE , check for proper function .

 

 

Ignition amplifier - also known to go bad on a 205's , causing various engine problems with the starting from cold and warm . Don't take it for granted if it has a spark while testing - cod be weak spark which isn't sufficient to ignite the mixture , or it may run out of spark once the amplifier heats up .

 

But since there's not fuel supply via injectors - chase that first (hope you do not have an immobilizer ?)

 

If you have fuel (an nice conical spray from the injectors) and spark (a good one , thick blue spark .. yellow/orange is an weak) , and good compression - check the timing belt if the engine is timed up properly .

 

Hope some of this sorts out your problem , if not , do not hesitate to ask us again .

 

D

Edited September 12, 2013 by DamirGTI

[jackherer 543]

Have you tried popping the plugs off the injectors to see if any of the wires have been pushed back? If there is one not making contact it will cause all not to fire

 

That's a valid point but it's not quite right, in your case the two pins must have been touching each other, otherwise the other three injectors will still fire.

[Tom Fenton 1,525]

 

That's a valid point but it's not quite right, in your case the two pins must have been touching each other, otherwise the other three injectors will still fire.

 

Agreed with this. I've had a car running on three before due to a pin being pushed back in one of the inj. plugs.

[Leet205 48]

 

That's a valid point but it's not quite right, in your case the two pins must have been touching each other, otherwise the other three injectors will still fire.

 

 

 

Agreed with this. I've had a car running on three before due to a pin being pushed back in one of the inj. plugs.

 

Yeah now that you mention it on one plug they were pushed back a lot so may have been touching.

[Tom Fenton 1,525]

Did you bend the "tab" back out so they clipped into the housing properly now? Or you can get replacement terminals and recrimp if needed.

[Leet205 48]

Did you bend the "tab" back out so they clipped into the housing properly now? Or you can get replacement terminals and recrimp if needed.

 

I did bent the retaining tab back out, so shouldnt be an issue in the future

[kevvy555 0]

Hi All,

 

All your help is much appreciated. Firstly i tested the pins in the injectors against the inlet manifold and got no power, as well as checking they were not pushed in. I checked the tachymetric relay and it did smell a bit like burnt electrics and on the underside there was a very light brown sort of stain, but all the bits look ok. After doing this i tried it again and the injectors worked and as expected it started.

 

Still however don't know what exactly was the problem but seems the tachymetric relay. So, now running it took it down the road with the following problems:

 

1. It wont tickover, but this maybe due to it not been warm enough, although the idle screw on the AFM was open quite a bit so i would expect it to idle as it did before.

2. Trying to drive along with say 1/4 throttle it hesitates then goes on and off making the car rock forward and backward as it goes, a bit like bunny hoping it but at like 20mph, hard to explain. If i floor it, then it picks up goes no problem. With it not been run in yet thou im limited in doing this. I think it probably also smoothes out when the revs get high, probably above 3500. Revs fine when stationary.

3. After it started getting hotter and more near running temperature it started to pop out the exhaust, not a backfire just popping every couple of seconds.

 

The popping may be the timing been out, but then it did't do this when i had it running before. Another problem i have is i cant time it as there doesn't seem to be a timing plate on it, i can see the marks on the flywheel but nothing to time against it. Have looked on ebay etc for a plate but cant find one, any ideas.

 

Any more suggestions would be great, unfortunately wont have much time this weekend to work on it as having friends come and stay, but im sure i will squeeze some time in.

 

Cheers

 

Kev

[kevvy555 0]

Have done some further investigation. Tried swapping the ecu with the old 1.6 which made little difference, still wont idle unless i turn the idle screw right out and at that it idling at 2000rpm.

Checked the plugs and they are starting to build up white on them, so it must be running lean.

Took out the ecu temperature sensor and that makes it run better, i guess its causing it to run richer.

 

Any comments much appreciated.

[welshpug 1,622]

sounds like its running lean, wind the AFM screw in a little.

 

your best bet is to grab a Haynes manual and thoroughly read up on the Jetronic LE2 system, how to setup and test the components.

[kevvy555 0]

Seems like there is quite a few things I can do to tune it which I will try, annoying thing is it won't start again now, think I'm gonna try a new tachymetric relay, just can see how it can be bad wires as I had it running, left it overnight and then in morning setup the throttle position switch not touching anything but that and the wire going to it and then it wouldn't start.

[kevvy555 0]

Update on this.

 

I replaced tachymetric relay, injectors and regulator.

 

The car will start now and i have got it running well, once warmed up it ticks over with a slight variation in revs between about 900-1100 at the extreme.

 

Thought i has solved the problem and then today after verifying the oil pressure (40psi idle, 80psi 4000RPM, guess this is fine), had it ticking over for a while and it just cut out and wouldn't restart. Took the injectors out, turned it over and no fuel, same problem as before.

 

Gave up and then thought maybe the AFM is sticking, actually just unplugged it, tried again and the injectors started working again.

 

Does this sound like AFM issues, it is a unit off a working car so i was told, but im just wondering now, cant think what else would cause this any ideas.

[DamirGTI 325]

If the flap moves freely it'll be wiring issue more likely - peel off the rubber boot from the connector and check the state of the wiring underneath .. the wires insulation often break or the contacts end up pushed on the inside on the AFM connector thus creating on/off contact in the presence of engine vibrations , but only being visible when you slide the rubber boot off to reveal the back side of the connector .

 

D

[kevvy555 0]

Took the car out for a longish drive, everything fine, for 30 miles. Stopped to check everything was ok, alternator bolt was loose so had to turn her off.

 

Restarted it, moved forward and hit a bump, cut out, wouldn't restart, no matter what i tried for 30 minutes no luck. Got frustrated and banged the tachymetric relay on the floor and then it started. Nearly home, went over a speed bump, cut out again, banged the relay again and it went again.

 

This of course points at the relay (despite replacing it), does this make sense, has anyone had similar experiences. Is it the relay or is it the wiring/connector, what is the best thing to do here, take the connector t bits? The connector itself looks fine, no corrosion.

 

Have ordered a new relay from gsf, hope this solves the problem.

 

Kev

[welshpug 1,622]

if any of the ignition connections is iffy and cutting spark the tachymetric relay will drop out.

[kevvy555 0]

A good point, however when it has done this in the past i have checked for spark and there is one, but then taken the injectors out to see no fuel coming from them, i will however double check the ignition connections.

[kevvy555 0]

Latest update. I have been taking the car out for much longer runs as it now starts reliably. I replaced the tachymetric relay with yet another one, a new one this time. I either have a new problem or its just the same problem.

 

After driving for about half hour to an hour it starts to briefly cut out, this keeps getting worse until it completely cuts out and then wont restart. After leaving it for between an hour and two hours it will then restart and run fine but eventually the same will happen again.

 

Seems like something is overheating, the only thing i can think of is the ignition module, would these symptoms seem like that or any other suggestions welcome.

 

kev

[kevvy555 0]

Reading

 

http://www.205gtidrivers.com/articles.html/_/articles-guides/engine-related/what-is-the-ignition-amplifier-r89

 

Points directly at the ignition amplifier (not module). I got a spare bosch one i am going to try.

 

Kev

[kevvy555 0]

Its got a ducillier one on it at the moment, have heard these are rubbish.

[DamirGTI 325]

Yes , Ducellier amps. are a bit poor quality .. old blue Bosch is by far the best amplifier , virtually never goes wrong despite it's manufacturing date .

 

D

[MikeC 10]

Does the Tachometric relay get warm or hot when in use? Mine i'm finding gets quite hot, and it is only new Cartier one.

Edited September 30, 2013 by MikeC

[DamirGTI 325]

Yes , a little bit ... there's pretty high current flowing through it .

 

Had some "funny moments" with this before :

http://forum.205gtidrivers.com/index.php?showtopic=84329

 

 

D

[MikeC 10]

Holy C**P Damir, lucky catch.

Thanks for the reply though, it's not getting that hot thankfully, as i can still touch it etc...